Interactive content
HD DVDs use the HDi Interactive Format to allow interactive content to be authored for discs. HDi is based on web technologies such as HTML, XML, CSS, SMIL, and ECMAScript (JavaScript), so authoring in HDi should be a fairly easy transition for web developers. No existing DVD authoring experience is required. In contrast, Blu-ray Disc content is authored using either a scripting environment for basic content, or a Java-based platform (BD-J) for advanced content. DVD video discs utilize pre-rendered MPEG segments, selectable subtitle pictures, and simple programmatic navigation which is considerably more limited.